Implementation of RTK for Property Surveys

Implementation of RTK for Property Surveys

146th ANNUAL REGIONAL CONVENTION

GEODETIC ENGINEERS OF THE PHILIPPINES

46TH GEP ANNUAL REGIONAL CONVENTION

(REGIONAL DIVISION III)

LOUIE P. BALICANTAChair, UPDGE

Director, UPTCAGPFelipe F. Cruz Professorial Chair in Geodetic Engineering

Survey, Land Administration and Valuation LaboratoryU.P. Department of Geodetic Engineering

[email protected]

Subic Bay Peninsular Hotel, Subic Bay Freeport Zone

February 14-15, 2020

L.P. Balicanta Y.F. Pagdonsolan & C.D. Flores


All civilizations that rose to an urban culture needtwo science-related technology:

• mathematics for land measurements

• commerce and astronomy for time-keeping inagriculture and aspects of religious rituals

- Frederick Seitzhttps://www.yumpu.com/en/document/read/48819103/namria-commences-inter-island-benchmark-connections

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https://www.yumpu.com/en/document/read/48819103/namria-commences-inter-island-benchmark-connections

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BACKGROUND


Size? Shape?Location?

PROPERTY SURVEY

2 major field activities1. Data gathering2. Stake-out


BACKGROUND


BACKGROUNDGNSS

Satellite Positioning Hotspothttp://intranet.eng.unsw.edu.au/system/files/satellitehotspot.jpg

Typical Session Lengths for Static and Rapid Static (Ghilani and Wolf 2008)

Typical RTK-GNSS Set-up

http://intranet.eng.unsw.edu.au/system/files/satellitehotspot.jpg


DENR Land Management Bureau (LMB) issued Memorandum Circular No. 2015-001, “Guidelines on the Use of Real Time Kinematic (RTK) Global Navigation Satellite System (GNSS) in the Conduct of All Kinds of Lot Surveys with Tertiary Accuracy”.

LMB issued MC No. 2015-001BACKGROUND

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BACKGROUND


Property Survey using RTK-GNSS

Calibration Baseline Establishment

Research

LandS Mode 2

Proper RTK CaliBER

LandS Mode 2 Research Team

University of the Philippines, Diliman

Training Center for Applied Geodesy And Photogrammetry


Research Coordinators

Department of Environment and Natural Resources

Land Management Bureau



RELATED CONCEPTS AND STUDIES

Coordinate System

• Local Plane Coordinate System• PPCS-TM/ Luzon 1911• PPCS-TM/PRS92

PGD 2016/2020

Results: from LandS Mode 1

Snapshot of the Cadastral Maps of Guiguinto overlaying the old PTM, Luzon 1911 and ITRFversions.

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PRS92

Old PTM

ITRF




Common Point

Dd<=10cm

DAO 2007-29



Common Point

The problem with the use of common point is that small amount oftranslation in the common point will result to an equivalent shift in thepositions of the subsequent surveys and the errors become cumulative whenusing different common points from different surveys (Fernandez, 1966)


RELATED CONCEPTS & STUDIESComparison between GPS derived and Astronomic Azimuths

• For rapid static survey, geodetic azimuths computed from loggedcoordinates and published coordinates of NAMRIA referencepoints are comparable at least within secondary accuracy(UPTCAGP, 2009)

• For project control, geodetic azimuth and astronomic azimuthcan be used interchangeably within secondary accuracy(UPTCAGP, 2009)


RELATED CONCEPTS

Azimuth• Astronomic Azimuth vs. Geodetic Azimuth vs. Grid

Azimuth

http://onlinemanuals.txdot.gov/txdotmanuals/ess/images/ess_fig3-7_geodetic_to_grid_azimuth.jpg

http://onlinemanuals.txdot.gov/txdotmanuals/ess/images/ess_fig3-7_geodetic_to_grid_azimuth.jpg


RELATED CONCEPTS

Distance• Ground Distance vs. Geodetic Distance vs. Grid Distance

https://www.spar3d.com/blogs/from-scratch/vol13no16-state-plane-coordinates/


RELATED CONCEPTS AND STUDIESRTK-GNSS Performance Under Tree Canopy

• The experiment conducted by Lucas in 2007 showed that thebest accuracy achieved by survey grade GPS receiver is 1.46meters using post processed kinematic technique (Lucas, GPSunder the Forest Canopy, 2007).

• Positional accuracy is degraded as the density of the canopyincreases and that positional update is delayed (Zheng, Wang, &Nihan, n.d.)

• A Research on the Effect of Different Measuring Configurations in Network RTK Applications (Kutalmis Gumus, 2015)

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• Determines whether there is a statistically significant difference between coordinates obtained under different elevation angles and measuring epochs through different correction methods in Network Real Time Kinematic Applications.




RELATED CONCEPTS AND STUDIESLMB issued MC No. 2015-001Salient conditions for RTK-GNSS use for isolated surveys(a) use of calibrated and tested dual frequency GNSS receivers(b) receiver clearance of 15o from the horizon(c) bipod support of poles with receivers during survey(d) use of electronic total station to augment RTK-GNSS(e) root mean square (RMS) value must be 35 or below(f) RTK observation length not less than two (2) minutes(g) minimum of five (5) satellites must be tracked (h) baseline length of 200 meters to 1 kilometer shall be

established using RTK instrument preferably not more than 1 kilometer from the lot

(i) list of required contents of observation field notes

• ISO-17123-8: International Standards for Checking GNSS Field Measuring Systems (Heister, 2008)

• standardized test for checkingif declared precision of receiver isachievable in field

• requires numerous observationsof distances to be compared to actual/known values (Di,j - D*)

• standard deviation frommeasurements is then compared todeclared standard deviation

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– “RTK-GNSS is applicable for parcel corner positiondetermination with consideration to limitations such asobstructions, level of accuracy, systematic error fromprojection, different coordinate systems used in thecountry, and poor identification of common points.”

– Considering the limitations of the study before and theevolving GNSS receiver technology, and update of findingsis necessary

– Model for Research Methodology

– GNSS models used were limited 21




METHODOLOGY

Workflow of the Experiments


Azimuths for RTK-GNSSRESULTS


Azimuths for RTK-GNSSRESULTS


Under Tree CanopyRESULTS


New SurveyRESULTS


New SurveyRESULTS


New SurveyRESULTS


Old SurveyRESULTS

COMMON POINT

Figure 6. Survey plan with technical description of Site 5 used for RTK-GNSS for Old Survey Experiment


Old SurveyRESULTS


Combined RTK-GNSS & Total Station MethodologyRESULTS

w/RTK-GNSS Limit?

YesNo



1. Rapid-Static GNSS Survey can be used in establishing controls for the survey.

- connect to old Bureau of Lands, NAMRIA or new DENR-LMS depending on the situation

- Established a pair for electronic total station use. - Baseline length can be short but at least 50 meters is suggested.

Control Survey



1. RTK-GNSS Survey can be used based on the conditions set by DENR-LMB Memorandum Circular No. 2015-001.

2. In addition surveyor can also consider the following conditions:(a) receiver clearance of 15o from the horizon can be waived if

GNSS receiver can provide positional error not more than five (5) centimeters under satellite-signal obstructions such as tree canopies

(b) rover receivers held is applicable if the circular bubble is balanced by the instrument man

(c) positional precision better than five (5) centimeters can be used as guide to a good observation if RMS is not provided

Isolated Survey Implementation



(d) observation time can be lessened to five (5) 1-second observations depending on the precision shown on the GNSS controller(e) minimum of 10 satellites are needed to have a good RTK-GNSS Survey results,(f) PDOP should be better than 2.

3. If these conditions are met, RTK-GNSS can be used for a specific property survey task. If not, the traditional method of using an electronic station should be used.

Grid azimuths and grid distances must be converted to geodetic azimuths and geodetic distances for total station use (especially for long sights)

Isolated Survey Implementation


CONCLUSION & RECOMMENDATION• RTK-GNSS was shown to be applicable in determining the

positions of parcel corners without significant differencecompared to traditional method (use of optical instrument)

• Suggested methodologies provided may be used by surveypractitioners in conducting property surveys using RTK-GNSSstand-alone or RTK-GNSS combined with an electronic totalstation.

• However, limitations exist such as obstruction, accuracy withincentimeter level and systematic error from projection

• RTK-GNSS like the traditional method is also affected by landsurvey conditions such as varying coordinate system and pooror wrong identification of common point.


CONCLUSION & RECOMMENDATION• Due to obstructions which cannot be avoided especially in

urban areas, a combined RTK-GNSS-total station survey is thepreferred technique.

• Since the main output of RTK-GNSS survey is in terms of gridposition there maybe a need to change the requirements forsurvey plan approval since traverse and lot data computationsusing side-shot data are not applicable.


CONCLUSION & RECOMMENDATION• It is recommended that part of the submittal information

include base-point used, horizontal precision obtained duringthe survey and PDOP.

• Solutions on getting the geodetic azimuth and distance mayalso be included since survey plans are currently in terms ofdirections and distances.

• Requirement to provide only grid positions can also berecommended.


CONCLUSION & RECOMMENDATION

• Problems pertaining to the three (3) existing coordinatereference systems in the current cadastral database and thepossible difference between the technical description of an oldsurvey and the result of RTK-GNSS on lot parcels were notcovered by the experiments.

• Surveyors must be aware of these issues when doing surveys tobe able to adjust to the situation and provide a sensiblesolution to a particular property survey problem.

Component 1Property Survey using RTK-GNSS

x

ProperRTK

46th ANNUAL REGIONAL CONVENTION 39

Proper RTKRationale and Objectives

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• Rationale

• As more survey practitioners are aware

on the advantages of using RTK-GNSS, an

implementing rules and regulations (IRR)

is needed to provide a proper way to use

of the technology and verify of the results.

• The IRR should contain not just the

standard processes and methodologies in

using RTK-GNSS, but also a way to verify

the survey outputs.

• The processes and standards described in

the IRR should have a proper basis and

tested if applicable.

• Objectives

• To come-up with variousmethodologies and techniques inevaluating the performance of eachGNSS-RTK model that can be used bysurveyors for property survey;

• To implement the tests andexperiments;

• To provide an IVAS process from surveyoutputs obtained from RTK-GNSS; and

• To come-up with an IRR on the use ofRTK for property survey using researchmethod.


ProperRTK Expected Outputs•Documentation of the different RTK-GNSS brands

and models available in the current market;

•Documentation on the specifications of the different RTK-GNSS brands and models;

•Technical Report describing the implemented test methodologies, statistical analysis and proposals for IVAS; and

•Draft Implementing Rules and Regulations (IRR).


Equipment Testing


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Thank you for your attention!!!

Try not to become a person of success, but rather try to become a

person of value - Albert Einstein


Documents

Implementation of RTK for Property Surveys